SWITCHYARD
Switchyard is a place where the entire primary protecting equipment of the
power system is arranged in a systematic manner from generator
transformer to feeders by connecting the transmission lines
It is a switching station which has the following credits
Main link between Generating station and
Transmission system.
Step-up and/or Step-down the voltage levels
depending upon the Network requirement.
Switching ON/OFF Reactive Power Control
devices, (such as reactors and capacitors) which has
effect on Quality of power.
As it handles large amount of power , it is considered
essential that it remains secure and serviceable to
supply the outgoing transmission system even under
condition of major equipment faults or bus bar faults.
Generally substation are relying on SCADA
(supervisory control and data acquisition system) for
remote supervision and control.
5. ABOUT RSTPS 400 KV SWITCH YARD
400 KV Switchyard of Ramagundam Super Thermal Power Station is the most
vital switching station in the southern Grid 2600 MW of Bulk Power generated
by three 200 MW Units and four 500 MW Units of NTPC Ramagundam is
evacuated for supplying to the southern states.
Switchyard consists of two 400 KV busbar systems fed by 7 Nos. of generator
feeders, 9 Nos of 400 KV feeders, 3 Nos of 220 KV feeders and two nos. of 132
Kv feeders as shown in the single line diagram of 400 Kv switch yard.
In addition to the above, three nos. of Tie Transformers, five nos. of Auto
Transformers and two nos. of Shunt Reactors are provided as shown in the
switchyard line diagram.
5.1. 400 KV TRANSMISSION LINES
1. Ramagundam Nagarjunasagar 1 Double Circuit lines (267
Circuit Km length)
2. Ramagundam Nagarjunasagar 2
Circuit
3. Ramagundam Hyderabad Circuit 1 Independent lines
4. Ramagundam Hyderabad Circuit 2 (189 Km length)
5 Ramagundam Hyderabad Circuit 3
6 Ramagundam Hyderabad Circuit 4
7. Ramagundam Khammam Circuit 1 Single line (202 Km length)
8. Ramagundam Chandrapur Circuit 1 HVDC back to back intergrid
9. Ramagundam Chandrapur Circuit 2 connecting double circuit lines
(180 Km length)
5.2 220 KV TRANSMISSION LINES
1. NTPC AP Transco line 1 Through 400 Kv/220KV
2. NTPC AP Transco line 2 250MVA A.T # 3 & 4
3. NTPC AP Transco line 3 Through 400 KV/220KV
315 MVA A.T # 5
5.3 132KV TRANSMISSION LINES
1. NTPC AP Transco line 1 Through 400 Kv/132KV
2. NTPC AP Transco line 2 200MVA A.T # 1 & 2
5.4AUTO TRANSFORMERS
Five Auto Transformers with on Load Tap Changers are provided to interconnect
the 400 Kv system of NTPC and 220/132 Kv system of ATransco, Malyalapally
substation situated 1.8 Km away from the RSTPS switchyard.
5.5 TIE TRANSFORMER
Four nos. of Tie Transformers are provided for feeding power to station
auxiliaries like Cooling water & Raw water pumps, Coal Handling & water
treatment Plants, Ash & Fuel Handling pumps, Cooling towers and lighting
requirements of station & colony.
5.6SHUNT REACTORS
Long lines when lightly loaded, the receiving end voltage raises, due to Ferranti
effect. Shunt Reactors produce lagging MVAR there by control the receiving
end voltages during lightly loaded conditions. Shunt reactors also limit the
short circuit fault levels. Therefore, Shunt reactors are provided on both the
ends of Nagarjunasagar lines 1 & 2, the length of these lines being about 267
km
7. SWITCHYARD EQUIPMENT
To perform switchyard operation activities perfectly, operation staff should have
good knowledge about the equipment provided in switchyard as well as in
control room. They should be familiar with the control system adopted here and
a good understanding about the procedures to be followed during the
emergencies, outage requirements and charging.
Equipment used in Switchyard are:
Transformers
Switch Gears
Circuit Breaker
Isolators
Earth Switches
Surge Arrestors
Wave Traps
Reactive Power compensating device
BUS Bars
Conductors / Auxiliary Items
Post Insulators and supporting structures
